JAXB was removed from Java 9+. In 2.164, JAXB was detached into the JAXB API plugin, which means that any plugin with a Jenkins baseline prior to 2.164 will get JAXB on its classpath via the detached plugin mechanism. Any plugin with a Jenkins baseline greater than or equal to 2.164 will get JAXB on its classpath if and only if it declares a plugin-to-plugin dependency on JAXB (recommended) or embeds JAXB into its own .jpi via a direct or transitive dependency.
A systematic search of the plugin corpus was conducted on May 9, 2022; this search revealed that a number of plugins have a baseline greater than or equal to 2.164, a direct or transitive usage of JAXB, no plugin-to-plugin dependency on JAXB, and no copy of JAXB in the .jpi. For compatibility with Java 11, these plugins should drop their usage of JAXB or should declare an explicit dependency on the JAXB, Jackson 2 API, and/or Jersey 2 API plugins.